A rare condition when a man's testicles are filled with blood, rather than semen. Many think this mishap is due to being repeatedly kicked in the testicles at a young age, but it is actually a hereditary desease.

Catie: Hey Riley, how did last night go with Sean?
Riley: Not so well, I got the bloodnut again.
Catie: Sucks to be you.
Sean: Who's next?